In the disclosure of U.S. Pat. No. 4,176,240, and U.S. Pat. No. 4,259,540 which disclosures are hereby incorporated by reference, a filling material for electrical and light conducting cable is described which provides water-proofing for underground telephone cable. The composition described in U.S. Pat. No. 4,176,240 for that use is said to be comprised of three components: (1) ASTM Type 104 A(naphthenic) oil having a minimum sp. gr. of 0.860, a minimum SUS viscosity at 210 degrees F. of 45, a maximum pour point ASTM D 97 of 10 degrees F. and a maximum of 5 percent aromatic oils; (2) a styrene-ethylene butylene-styrene block copolymer having a styrene-rubber ratio of approximately 0.4 and (3) a polyethylene having a softening point of 110 degrees C. to 130 degrees C. The composition of U.S. Pat. No. 4,259,540 is similar, but the oil may be paraffinic or naphthenic with a somewhat higher maximum pour point and the block copolymer styrene-rubber ratio may be from approximately 0.2 to 0.5.
Such cable fill compositions as described in the above mentioned patents are deficient in use in that they have two severely limiting properties; namely: (1) when the temperature approaches 150.degree. F. the fill material drips out of the cable, and (2) the temperature at which the cable is filled is limited to 110.degree. C. (230.degree. F.) because of the potential damage to the polyethylene insulation at a higher temperature, but even at this temperature the viscosity of the prior art cable fill is not sufficiently low (i.e., fluid) to ensure that all of the crevices in the bundle of wires will be filled with the waterproofing composition. This is particularly true for cable cores having 500 or more wire pairs. This invention increases the utility of a gelled oil composition significantly, not only making it suitable for cable makers who require at least 170.degree. F. drip temperature, but since the viscosity of the improved composition is about one-half of that of the prior art composition at the filling temperature, greater assurance is obtained that the cables will be completely filled and the risk of damaging insulation during filling is also reduced since lower fill temperatures can be used. In addition, this invention enables cables with a large number of wire pairs to be filled reliably without the need to preheat the core as is sometimes done in using the gels available heretofore.